Ceramic/organic multilayer interconnection board

Abstract

A multilayer board comprising a novel construction of ceramic and organic layers to reduce difficulties commonly encountered by board materials and components attached thereto having differing thermal coefficients of expansion. The multilayer board comprises an inorganic ceramic surface which is affixedly attached via a compliant adhesive to a conventional plated up post or plated thru hole organic multilayer board.

Now that the invention has been described, what is claimed is: 
     
       1. A ceramic/organic multilayer board functioning to reduce the thermal coefficient of expansion mismatches between component carriers mounted on said multilayer board comprising in combination: an organic inner layer having a top and bottom surface;   a duality of compliant adhesive layers each respectively positioned on said top and said bottom surface; and   a duality of inorganic ceramic layers each respectively affixed to said compliant adhesive layers.   
     
     
       2. The ceramic/organic multilayer board as set forth in claim 1, wherein said organic inner layer further comprises a plurality of electrically conductive pathways. 
     
     
       3. The ceramic/organ ic multilayer board as set forth in claim 1 wherein said compliant adhesive layers are selected from a group of materials, having good thermal conductivity and a low modulus of elasticity comprising epoxy nitrile or modified acrylic adhesive. 
     
     
       4. The ceramic/organic multilayer board as set forth in claim 1, wherein said inorganic ceramic layers are constructed from a group of materials comprising mullite, beryllium, silicon nitride, aluminum nitride and any combination thereof. 
     
     
       5. The ceramic/organic multilayer board as set forth in claim 2, wherein said ceramic layers further comprise electrically conductive footprints positioned thereon and being connected through said adhesive layers to said plurality of said electrically conductive pathways. 
     
     
       6. The ceramic/organic multilayer board as set forth in claim 1, wherein said ceramic layers are cut short to expose said organic inner layer for the direct electrical connection to foreign devices. 
     
     
       7. The ceramic/organic multilayer board as set forth in claim 2, wherein said inner layer's top and said bottom surfaces have conductive pads thereon electrically connected to said plurality of said electrically conductive pathways. 
     
     
       8. A ceramic/organic multilayer composite structure comprising in combination: a conventional organic multilayer board having a top side and a bottom side;   an adhesive applied to said top and to said bottom side; and   an inorganic ceramic layer affixed to said top and to said bottom side via said adhesive, said adhesive being disposed between said conventional multilayer board's top and bottom sides and between said inorganic ceramic layers.   
     
     
       9. The ceramic/organic multilayer composite structure as set forth in claim 8, wherein said ceramic/organic multilayer board has electrical connections selected from the group comprising plated thru holes, plated up posts, and a combination of both. 
     
     
       10. The ceramic/organic multilayer composite structure of claim 8, wherein said adhesive is selected from a group of materials having good thermal conductivity and a low modulus of elasticity comprising epoxy nitrile or modified acrylic adhesive. 
     
     
       11. The ceramic/organic multilayer board composite structure of claim 8, wherein said inorganic ceramic layers are constructed from a group of materials having a thermal coefficient of expansion similar to that of alumina comprising mullite, beryllium, silicon nitride, aluminum nitride and any combination thereof. 
     
     
       12. The ceramic/organic multilayer board composite structure as set forth in claim 11, wherein said ceramic layers further comprises electrically conductive footprints positioned on the surface of each said inorganic ceramic layer. 
     
     
       13. The ceramic/organic multilayer board composite structure as set forth in claim 12, wherein said electrically conductive footprints are connected through said adhesive to said multilayer board. 
     
     
       14. A multilayer board comprising in combination: an organic layer forming a printed circuit board;   a compliant adhesive layer positioned on said organic layer; and   an inorganic ceramic layer positioned atop said compliant adhesive layer.